1. Field of the Invention
The present invention is generally directed to an air-insulated substation feeder assembly comprising a modular and/or collapsible configuration in order to facilitate a substantial amount of preconstruction, preassembly, and pretesting off-site or otherwise in a factory prior to installation within a power system or grid.
2. Description of the Related Art
Power plants, generating stations and/or power stations are industrial facilities located around the country and the World which are specifically constructed or otherwise configured for the purpose of generating electrical power that is ultimately distributed to residential and commercial areas for consumption or use. In particular, the power plant typically includes or is connected to one or more transmission substations that convert the voltage of the generated power up to extremely high levels for long distance transmission on a transmission grid.
Before the power can be utilized in a home or business, the voltage must be stepped down from the transmission grid to the distribution grid. Once the voltage is stepped down into the distribution grid, the power can be distributed to the various homes or buildings via a power substation and/or a substation feeder. In particular, most power substations include one or more voltage transformers that are specifically configured to step the transmission voltages (typically in the range of 150,000 volts to 750,000 volts) down to a level (typically less than 10,000 volts) that is capable of being distributed to the end user at a residential home or commercial building. In addition to a number of electrical components, discussed below, the substations also include a transmission bus that is used to distribute the power off into multiple directions, and circuit breaker(s) and/or switch(es) that are used to disconnect the substation from the grid when desired or when necessary.
There are two main types of substations—gas-insulated substations (“GIS”) and air-insulated substations (“AIS”). A gas-insulated substation is an electrical or power substation wherein the major components are housed in a sealed and controlled environment. Within such an environment, gas (e.g., sulfur hexaflouride) is used as the insulating medium. Gas-insulated substations are typically used in areas where the substation needs to be compact or otherwise occupy a relatively small area. As such, gas-insulated substations are generally found in highly populated and developed areas with very little room for larger, air-insulated substations. On the other hand, air-insulated substations use air as the insulating medium and the major components are exposed to the outer elements. In general, gas-insulated substations are more expensive than a similarly functioning or similarly rated air-insulated substation.
Moreover, air-insulated substations are typically assembled, constructed or otherwise built on-site in that all of the various electrical components, including various insulators, transformers, reclosers, circuit breakers, switches, bushings and the transmission bus are all connected and assembled at the desired location. Assembly of the substation is extremely laborious in nature and may take several weeks or even months to complete. Once assembled on-site, the various electrical components are tested or measured to make sure the subsystem is in working order. If it is not, the laborers must then troubleshoot the assembled substation on site in an attempt to locate the malfunctioning component(s), which may be virtually any component, including a malfunctioning transformer, cracked or broken insulator, loose bushing, etc. Depending upon the number and nature of the malfunctioning component(s) and the ease of fixing the malfunctions, the substation may not be ready for use for several additional days, weeks or even months. This process, of course, can cost a great deal of money once all of the components are finally installed and in general working order.
The proposed modular substation feeder assembly as described herein is intended to overcome these and other obstacles. In particular, because of the unique and novel configuration of the various components, the modular substation feeder assembly of the present invention is capable of being substantially preassembled in a factory or other off-site facility. This allows for testing and troubleshooting prior to disposition of the substation on-site, eliminating the unnecessary labor efforts in construction, assembly and testing on-site. The factory may also be used to preassemble or manufacture other components of the transmission and/or distribution grid, including recloser assemblies, transformers, transmission stations, switches, etc., thereby further reducing costs and time.